Switch for radio phonograph sets



A ril 25, 1933. F. c. DE REAMER 1,905,689

SWITCH FOR RADIO PHONOGRAPH SETS Filed Feb. 3, 193].

6 Fjgl.

Inventor- His Aifiorneg.

Frank C. De Reamer Patented Apr. 25, 1933 UNITED STATES PATENT OFFICE "FRANK C. DE REAMER, OF BRIDGEIOR'I, CONNECTICUT, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK SWITCH FOB RADIO PHONOGBAIH SETS Application flied February a, 1931. Serial No. 513,1a4.

For certain classes of work it is necessary to employ small, compact switches to efi'ect a relatively large number of circuit combinations which vary for different conditions or mode of operation of the apparatus con trolled or associated therewith. To make a new switch each time a change is made in the circuits is an expensive proposition initially and also means that stocks of the various 1o switches must be kept on hand to supply the demand.

My invention has for its object to avoid the objection above mentioned and to provide a switch structure composed of a numher of standard parts by means of which a large number of circuit combinations may be effected by merely assembling said parts in different relations or ways.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the drawing which is illustrative of my invention Fig. 1 is a plan View of the switch with the cover of the casing removed; Fig. 2 is a cross-section taken on line 2-2 of Fig. 1; Fig. 3 is a cross-section taken on line 33 of Fig. 1; Fig. 4t is an exploded perspective View and Fig. 5 is a detail.

My improved switch may be employed for a variety of purposes, the one shown being intended for use with a radio phonograph set for operation in a home recording device for recording on a phonograph record sounds received through a microphone or through a radio receiving set.

Referring to the drawing, 6 indicates a metal casing comprising a flat base and vertically rising end pieces 7 in which are bearings for the switch spindle 8. The cover of the casing has been removed to show the interior parts. The casing and all of the parts are made as small as possible to conform to the requirements 45 of the apparatus associated therewith. 9

indicates a drum made of insulatin materlal, as will be explained later, w ich is mounted on the spindle 8. On the drum are segmental contacts 10. The numeral 11 indicates a block of insulation of Z-shaped sectlon, as shown in Fig. 2, which is secured to the base by screws. The upper part of the block is provided with a large number of rec tangular slots 12 in which flexible contact fingers 13 are secured by rivets or other means. The rear end of each finger has a wire receiving opening, the wires for which enter through holes 11a in the insulating block.

The spindle 8 where it passes through the so parts of the contact carrying drum is given a square or other suitable shape to prevent relative rotation of the drum and spindle.

The drum comprises relatively small disks 14 and relatively large disks 15 both made 05 of material having good insulating properties. The small disks may be made of a suitable moldable composition composed of finely divided insulating material and a binder. The large disks may be made of the same "(0 material, or as shown of vulcanized fiber punched out of sheet stock. The disks are interspaced on the spindle, first a large and then a small disk. All of the large disks have a square central opening and at least one socket 16, some have two and others three or four sockets, depending upon the arangement of the contacts. The maximum number is dependent upon the number of operating positions of the drum when in use. The sockets are aligned with the peripheral surfaces of the small disks so that when the parts are assembled the segmental contacts will lie on said peripheral surfaces and be held in position solely by the large disks, thereby avoiding the necessity of numerous small securing means. The fact that the contacts are so supportedbetween their ends means that they can be made of very thin metal. Some of the large disks also have radial open ended slots 17, the walls of which engage the drum contacts and prevent relative angular movements. In addition to holding the segmental contacts, the large disks also act as arriers between the contact fingers to prevent surface leakage. All of the small disks are alike, each having a square opening in the center and four shallow, axial grooves 18, the purpose of which is to prevent the contact fingers as they rub on the peripheral surface from dragging metal particles from one moving contact to another which would short circuit the same to a greater or less degree. Experience has demonstrated that this dragging of the metal which metalizes the surface of the disks to a greater or less extent is a serious matter and that by the use of the grooves the objection is entirely avoided. In this connection it is to be remembered that small cur- .0 rents are being dealt with and that leakages are serious matters.

The disks are held on the spindle between an abutment 19 and a pair of nuts 20 at the other end of the spindle. The abutment is also used as a part of a device to position the drum in its step-by-step movements, the other part being in the form of a spring 21 which successively engages the notches 22 in the periphery of the abutment. 23 is a split piece of metal having a projecting end which by engaging the base of the switch, first on one side of the axis of the spindle and then on the other, serves as a stop means to limit the angular movement of the drum. 24 indicates a handle by which the drum is turned.

The segmental contacts 25 are made of thin sheet metal, such as brass, and are so curved as to sun ly fit the peripheral surfaces of the small disks. Each contact has a pair of small tenons 26 which fit into the sockets 16 formed in the large disks. These contacts may be varied in length or in width or both to suit the circuit requirements. As shown, the short ones span two of the small disks and rest thereon. The long ones span three such disks. Of course, the span may be greater if desired. As shown, the short contacts connect two circuits through the flexible contact fingers 13 and the long contacts connect three circuits through said fingers. The angular disposition of the contacts is such that the switch drum has four operative positions where circuits are completed. In other words, there is no position where the circuits are interrupted but such interruption can be obtained if desired by merely omitting contacts. Each contact also has a notch 27 along one edge. It is desirable to notch both side edges as shown rather than one, as it makes a better and more symmetrical construction. The tenons on the contacts hold the same against axial and radial movements, and the side walls of the radial slots 17 assist in preventing relative circumferential movements. Certain of the larger disks form a support neoaese which is common to a air of axially aligned contacts as shown in Big. 5. In order that there may be no current flow from one contact to the other, in such cases the tenons are purposely made so short that when the contacts are assembled they are separated by a suitable air space to insulate them. As a matter of simplification in manufacture and assembl the tenons on all of the contacts are made of the same length which is less than one-half the thickness of the lar e disks. By proper assembly of the thin an thick disks and the long and short segmental contacts a wide variety of circuit arrangements can be obtained. For example, at the present time four different switches are being made, each having different circuit arran ements but all using identically the same ind of parts. Obvlously, many other circuit arran ements can be made by proper selection an assembly of the parts.

Fig. 4 illustrates how the various disks are threaded on the spindle and how the se mental contacts are mounted in place. B y giving suitable assembling data to the operative any desired combination of parts can be obtained, it being merely a question of selecting the proper large disks and the proper segmental contacts. An outstanding advan of the construction is the fact that the act of stacking or threading the disks on the spindle in the proper order and an lar relation automatically positions the soc ets to receive the contacts. The contacts are inserted as the assembly progresses, and the whole structure is held together by a clamping means at one end.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. A rotary switch comprising a spindle thick and thin disks alternately arran thereon, the thin disks having axially extending sockets, thin metal contacts mounted on the thick disks, certain of which are in the same axial alignment, and shallow tenons on the contacts which enter the sockets, the aggregate length of a pair of tenons entering the same socket being less than that of the thickness of the disk containing the same.

2. A rotary switch comprising a. spindle, a plurality of disks of molded insulation, a plurality of thin punched disks of insulation interspaced with the molded disks, segmental. contacts resting on the riphe of the molded disks and held in p ace sole y by said thin disks, an abutment near one end of the spindle against which one of the disks is seated, and a clamping means located near the other end of the spindle which clamps all of the disks in place.

3. A rotary switch comprising a spindle, a drum mounted on the spindle to turn therewith, said drum comprising interspaced disks of different diameters, an larly di laced sockets in all of the larger disks, radi slots in certain of said disks, metal contacts mounted on the peripheral surface of the smaller disks, tenons at the ends of all of the contacts which are seated in the sockets, notches in the contacts registering with the slots, the walls of which prevent independent angular movements of the contacts, an insulating support, a plurality of contact fingers secured to the support and extending over the drum into engagement with the contacts thereon as the same are rotated, and a casing for the switch parts. h In} witness whereof, I have hereunto set my an FRANK C. DE REAMER. 

